Brake-lining.



W. G. HOFMANN.

BRAKE LINING.

APPLICATION FILED MAY 22, 1914.

1,120,617, Patented De0.8,1914.

WITNESSES. lflVE/VTOR 5 M I B) A TTOR/VEY STATES PATENT OFFICE.

WILLIAM G. HOFMANN, OF MILFORD, CONNECTICUT, ASSIGNOR T0 JOEL T. WOOSTEB,

or nnin'enronr, CONNECTICUT.

BEAKE-LINING.

Specification of Letters Patent.

Application filed May 22, 1914. Serial No. 840,249.

To all whom it may concern:

Be it known that I, WILLIAM G. Hor- MANN, a citizen of the United States, residing at Milford, county of New Haven, State of Connecticut, have invented an Imrovement in Brake-Linings, of which the ollowing is a specification.

This invention has for its object to produce a lining or friction material, especially adapted for use in automobile brakes, and for friction shoes, clutch pads, &c., where a high coefficient of friction is required and where there is great pressure and tendency to develop heat. With this end in view, I have devised the novel friction lining which I will now describe, in which longitudinal rooves are provided in the operative sur ace to serve as channels for oil in the class of brakes which run in oil,and as air spaces in brakes where no oil is used.

In the accompanying drawing forming a part of this specification, the figure is a perspective illustrating my novel lining.

The fabric is made by weaving asbestos yarn, which may or may not as preferred have a wire strand, about a lurality of relatively large fillingcords, t en treating the woven fabric by immersion in a hardening compound and then hot-calendering the treated fabric by passing it through hot calendaring rolls, one of which is smooth and the other ribbed and grooved to permanently form in the fabric longitudinal channels between the cords.

10 denotes woven asbestos yarn, 11 the filling cords, and 12 the channels in the fabric between the cords. The weaving may be done upon an ordinary asbestor loom set up with the filling cords properly spaced apart and running in the direction of the warp threads. Any number and size of the filling cords may be used, depending of course upon the width of the strip of fabric to be woven and the special use for which it is intended. The special hardening compound used is immaterial so far as the present invention is concerned. It is suflicient for the pur oses of this specification to state that the fa ric as completed by the loom is treated by immersion in any suitable hardening compound. If preferred, and in orderto shorten the time required for suitably treating the completed-fabric, the cords may be treated by immersion in the hardening compound before being set up in the loom.

After the hardening treatment, the chan-- nels are permanently formed theoperative side of the lining betweenthe cords by passing it between hot calendering rolls, one of which is smooth and the other provided with grooves to receive the asbestos covered cords and with ribs which permanently form the channels. The effect of this calendering operation is to partly dry and to perma nently harden and set the fabric, the channels formed between the cords in the completed lining being permanent and lasting as long as the fabric itself.

It is of course well understood that asbestos fabrics for brake linings and similar uses after the hardening treatment will not absorb oil, and consequently that as these fabrics have heretofore been woven'there-is little space for oil'between the lining and the. surface with -,which it' co-acts. This objection is wholly .overcome in my novel lining, as the channels between the cords hold an appreciable quantityof oil which necessarily comes into contact with the brake drum and is. effectually spread over the surface of the drum by centrifugal action.

My novel brake lining is equally effective upon the class of brakes that do not run in oil, as the channels serve as air spaces and the air contained therein acts to a marked degree in reducing the heat generated by the frictional contact of the lining withthe drum.

Having thus described my invention I claim:

1. A lining of the character described formed from woven asbestos and impregmated with a hardening compound. and having its operative face tudinal channels.

2. A lining of the character described formed from asbestos woven apart longitudinally disposed cords and treated with a hardening compound and having formed in its operative face longi: tudinal channels between the cords.

provided with longi about spaced i 3. The process of making fabric for, brake linings and similar uses which consists in weavin asbestos yarn about spaced apart longitu inally disposed cords, then immers ing the fabric in a hardening compound and finally rolling the same under heat and forming in the operative face thereof longiforming in the operative face thereof longi- 10 tudinal channels between the cords. tudinal channels between the cords.

The process of making fabric for brake In testimony whereof I aflix my signalinings and similar uses which consists in ture in presence of two itnesses.

5 immersing the cords in a hardening coma:

pound, spacing said cords apart and weav- WILLIAM HOFNN' ing asbestos yarn about them, then immers- Witnesses: ing the fabric in the hardenin compound H; MnAnE,

and finally rolling the same uner heat and E. M. CUL 

